Manual override system for rotary magnetically operated valve

ABSTRACT

A manual override for a magnetically operated rotary valve (10) is provided. The valve includes a rotary member connected to an internal carrier (18) that carries a plurality of permanent magnets (20). A rotary drive carrier (22) also carries a plurality of permanent magnets (24) and is separated from the internal carrier (18) by a hermetic barrier member (42). At one end the barrier member (42) is affixed to a rotatable plate member (26) that is held stationary by a removable pin (64) that interconnects the plate member (26) and a support member (56) affixed to the valve body (12). Rotation limit means are constituted by a pin (40) on the driven portion of the valve which is received in a cooperating recess (36) in the plate member (26). If the valve member jams and there is not sufficient magnetically-induced torque to free the valve member then the override of the invention will come into play. The removable pin (64) is removed and a lever (76) is attached to the plate member (26) to effect rotation thereof until there is engagement between the rotation limit means (40, 36). Continued rotation of the plate member (26) transfers rotative torque through the rotation limit means (36, 40) to the valve member until the valve member is freed. With the invention it is possible to transfer much more torque to the valve member than is normally available through the magnetic drive.

The present invention relates in general to rotary magnetically operatedvalves and in particular to a manual override system for such valves.

BACKGROUND OF THE INVENTION

Rotary magnetically operated valves are well known, one such valve beingdisclosed in Canadian Patent No. 1,092,589 issued on Dec. 30, 1980 toNova Scotia Research Foundation Corporation. Such a valve is used tocontrol the flow of a substance such as a liquid or a gas, the valvehaving particular value when the fluid flowing therethrough is hazardousdue to toxicity, radiation or corrosion. The valve of the Canadianpatent has its valve member, e.g. a butterfly, attached to a valve stemwhich is rotatable on a rotation axis and which is also attached to acarrier. The carrier mounts a plurality of rare earth magnets about itsouter periphery, with adjacent magnets having alternate polarity. Thecarrier is enclosed by a barrier member which is hermetically sealed tothe valve body so that hazardous material passing through the valve isalways contained within the barrier member and the valve body.

Externally of the barrier is another carrier, usually annular in shape,this carrier mounting another plurality of rare earth drive magnetsabout the internal circumference thereof, these magnets also being ofalternating opposite polarity. A suitable means such as a handle, valveactuator or lever arm is provided to effect rotary movement of the drivecarrier relative to the stationary barrier. Magnetic interaction acrossthe barrier member causes the internal driven carrier to follow therotary movement of the external drive carrier so that the valve memberis rotated to progressively open or close the valve. Rotation limitmeans can be provided to prevent the valve member from rotating too farin the valve body.

Valves in accordance with the above patent are able to handle heavy flowvolumes and the size of the valve member can be very large inasmuch asthe magnetic drive can produce high torques. On occasion, however, avalve may jam and the torque available magnetically is not sufficient toovercome the jam. It is therefore imperative that there be somemechanism available to override the magnetic operation of the valve sothat the valve can be either opened or closed by hand until such time asthe fault which caused the jam can be rectified. Usually the fault issuch that the valve must be dismantled, repaired, and rebuilt; otherwisethere would have been no problem in the first place.

SUMMARY OF THE INVENTION

The present invention meets the above requirement by providing a systemthat will allow the valve member of a stuck valve to be rotated to anopen or closed position shortly after a fault has been discovered and ithas been determined that the valve member cannot be rotated in the usualmagnetic manner. The elements of the present invention do not impact onthe usual operation of the valve and in fact several years of operationmay pass before the invention is called into play. However, given thesubstantial pressures that can be developed in hazardous environments,such as nuclear reactors, the availability of the present inventioncould save countless lives and prevent inestimable property damage byallowing an otherwise damaged valve to be operated so as to avoid anincreasingly dangerous condition.

The present invention provides a modified valve construction wherein thebarrier member is hermetically sealed to a lower plate member which isrotatable relative to the valve body. The plate member and the valvestem (or the internal carrier) have cooperating means that definerotation limit means. Normally the plate member will be held stationaryby appropriate means, such as a removable pin, which interconnects theplate member and a support member fixed to the valve body. With the pinin place the valve member will move as required, following the movementof the drive magnets as they impart rotary movement to the drivenmagnets and their carrier. Such movement of the valve member will onlybe between the rotational limits established by the cooperating meansmentioned above.

Typically the cooperating means will entail a pin carried by either theplate member or the valve stem (or the internal carrier) and acooperating recess in the valve stem (or the internal carrier) or in theplate member, the recess having end walls against which the pin willabut at the rotation limits of the valve member.

Should the valve member jam for any reason and there not be enoughtorque available magnetically to rotate the valve member the manualoverride system of this invention can be used. The removable pininterconnecting the support member and the plate member is withdrawn topermit relative rotation between the plate member and the valve body.Then, a lever is attached to the plate member so that a rotative forcecan be applied thereto. Movement of the lever will rotate the platemember until there is abutment between the pin and the recess end wallof the rotation limiting means. Continued application of a rotativeforce on the lever should then cause the plate member and the valvemember to rotate in concert due to the interaction of the rotationlimiting means until the valve is either opened or closed as required.

Eventually, the flow of fluid to the valve in question should be stoppedor diverted so that the valve can be isolated and repaired as necessary.

In summary therefore the present invention can be considered asproviding a manual override system for a rotary magnetically operatedvalve assembly having a valve member rotatably located in a valve bodyon a rotation axis, a first carrier member connected to the valve memberand mounting a peripheral set of driven magnets, a barrier membersurrounding the carrier member and being hermetically sealed to arotatable lower plate member of the assembly, a second carrier membersurrounding the barrier member and mounting a set of drive magnets formagnetically inducing following rotary movement in the first carriermember and the valve member in response to specific rotary movement ofthe second carrier member, and rotation limit means cooperativelyprovided on the lower plate member and the first carrier member, themanual override system comprising: a support member fixed to the valvebody; disengageable means normally interconnecting the support memberand the lower plate member to hold the lower plate member stationary;and lever means engageable with the lower plate member followingdisengagement of the disengageable means for forcing rotation of thelower plate member and consequent rotation of the valve member throughthe limit means in the event that the drive magnets are unable to effectrotary movement of the driven magnets.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial vertical section through a valve incorporatingthe override system of the present invention.

FIG. 2 shows a section on the line 2--2 of FIG. 1.

FIG. 3 shows a section on the line 3--3 of FIG. 1.

FIG. 4 shows a plan view of a lever used with the present invention.

FIG. 5 shows a section similar to that of FIG. 3 but with the inventionin operation.

FIGS. 6A and 6B show other forms of rotation limit means.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a rotary magnetic valve 10 modified in accordancewith the present invention. With reference also to FIG. 2 it is seenthat the valve 10 includes a valve body 12 which is connectable at eachend thereof to suitable conduits through which a fluid to be controlledwill pass. The valve body 12 contains a rotatable valve member (notshown), such as a butterfly, which is rotatable on a rotation axis 14. Avalve stem 16 extends from the valve member on the rotation axis and isconnected to or is part of a cylindrical first carrier member 18 whichhas driven rare earth magnets 20 mounted thereon about its outerperiphery as seen in FIGS. 1 and 2. The details of the mounting of suchmagnets are not necessary for a full understanding of the presentinvention, reference to Canadian Patent No. 1,092,589 being suggestedfor such details if necessary. Peripherally adjacent magnets are ofopposite polarity.

An inverted cup-shaped second or external carrier member 22 has aplurality of rare earth magnets 24 mounted on the inner peripherythereof, each magnet 24 being radially alignable with a correspondingmagnet 20 as seen in FIG. 2. As with the magnets 20 peripherallyadjacent magnets 24 are of opposite polarity.

Concentrically mounted exteriorly of the valve stem 16 is a circularplate member 26 having an annular depending boss or shaft portion 28that is journalled on the valve stem 16. The boss portion 28 extendsdownwardly to meet the top of the valve body 12 to which it is attachedwith a sealed interface 29. The sealed interface 29 is constructed sothat, while static in normal operation, it will allow rotation about itsaxis in an emergency. The plate member 26 has an annular outer recessedshoulder portion 30 to which an annular ring 32 is bolted bycircumferentially spaced bolts 34 (see FIGS. 1, 3 and 5). With referenceto FIGS. 3 and 5 it is seen that the plate member 26 has a pair ofdiametrically opposed preferably arcuate recesses 36 extending overabout 90°. Each recess 36 has a fiat wall 38 at each end thereof. Thevalve stem 16 carries a solid, strong diametrically extending pin 40which projects at each end thereof beyond the stem 16 into the adjacentrecess 36. Together, the recesses 36 and the pin 40 define cooperatingmeans which constitute rotation limit means for the valve. Although thepin 40 is shown as extending at each end into an adjacent recess 36 itshould be understood that a pin projecting beyond the valve stem only atone end into a single recess contained in the plate member could be usedif desired.

The annular ring 32 clamps a barrier member 42 to the plate member 26 soas to hermetically seal the barrier member to the plate member. Thecylindrical barrier member 42 separates the driven magnets 20 from thedrive magnets 24 and includes a disc-like end wall 44 which has opposedaxial boss and counterbore portions 46,48 respectively. The boss portion46 is journalled in a counterbore 50 of the carrier 18 so that thecarrier 18 can easily rotate within the barrier member 42. Thecounterbore portion 48 receives the cylindrical end of a drive-member 52which is bolted to the external carrier 22 and in turn is connected to asuitable valve actuator 54 such as a servo motor or other appropriatemeans.

A support member 56 in the form of a pair of straps 58 has its upperends bolted to the drive member 54 and its lower ends bolted to thevalve body 12 as best seen in FIG. 1. One of the straps 58 has a hole 60extending therethrough, the hole 60 lining up with a radial bore 62 inthe annular ring 32. A retaining pin 64 has a pull ring 66 attached to acentral cylindrical portion 68 which in turn terminates in a smallercylindrical portion 70. Portion 68 has a pair of protrusions 72 whichcan be spring loaded or made retractable so that portion 68 may fit intohole 60. The retaining pin thus described is commercially available andis shown here as an example of an appropriate retaining means, it beingunderstood that other functionally equivalent means could be used.

When the pin 64 is inserted through the hole 60 so that the portion 70fits in the bore 62 it will hold the plate member 26 rotationallystationary relative to the valve body 12. The protrusions 72 will engagethe rear face of the strap 58 so as to prevent the pin 64 frominadvertently slipping out of engagement with the bore 62.

With the valve assembly having its components in place as seen in FIGS.1-3 the drive carrier can be actuated so as to rotate on the axis 14.Due to magnetic interaction across the barrier 42 the driven carrierwill follow the drive carrier and rotate the valve member in the desireddirection. The plate member 26 is held stationary by the pin 64 andhence the valve member is constrained to rotate between rotationallimits determined by interaction between the pin 40 and the end walls 38of the recesses 36.

In the event that the valve member jams and there is not sufficientmagnetically induced torque to rotate the valve member one will first ofall remove the pin 64 by pulling it radially away from the bore 62 viathe ring 66. This is shown in FIG. 5, the pin having been completelyremoved from its interengaging position between the strap 58 and theplate member 26. The protrusion 72 will compress inwardly during theremoval step to allow complete removal of the pin.

With the pin 64 removed one then applies a lever member 76 as seen inFIG. 4 to rotate the plate member 26. The lever is a rectangular memberhaving an arcuate cutout 78 in one edge adjacent one end, and a straightopposite edge 80. The cutout 78 is mated to the cylindrical boss 28 ofthe plate member 26 and the edge 80 is pushed against a suitableabutment such as the head of one of the bolts 34. A force normal to thelength of the lever 76 is applied at the outer end thereof as seen inFIG. 5 (arrow A) to cause the plate member 26 to rotate relative to thevalve body 12. This brings one set of end walls 38 of the recesses 36into contact with the projecting ends of the pin 40. Continued forceapplication transfers rotative movement from the plate member 26 to thepin 40 and therethrough to the valve stem. It should be possible toapply sufficient force through the lever 76 to overcome the forcescausing the valve member to jam and to move the valve member to an openor a closed condition as desired. Applying the lever 76 in a manneropposite to that shown and applying a force opposite to the arrow Awould effect rotation in the opposite direction to move the valve memberto an open or closed condition as required. Once the valve member hasbeen moved to its desired condition it should be possible to shut downthe fluid flow elsewhere so that the fault which caused the valve memberto jam in the first place can be corrected. When the valve is ready tobe put back into service the pin 64 will be reinserted through hole 60to engage with the bore 62 and to again hold the plate member 26stationary with respect to the valve body 12.

It should be noted that during the described emergency manual operation,when the plate member 26 and its cylindrical boss 28 are rotated, thesealed interface 29 is made to rotate. Normally, this sealed interface29 is static and will likely operate in this condition for many years.It is only during the emergency manual operation that the interface 29is required to rotate with respect to the valve body 12, and even thenit is rotated slowly and only through a fraction of a turn, depending onwhat is required to open or close the valve.

As indicated hereinabove many details respecting the valve assembly havebeen omitted as being unnecessary to a complete understanding of theinvention. It will be appreciated that seals and/or bearing members willbe required between certain elements of the assembly but the naturethereof will be determined by the environment in which the valveassembly is to be used. It will also be appreciated that otheralternative constructions could be used without departing from thespirit of the invention. For example the rotation limit means could takethe form shown in FIG. 6A wherein the plate member 26 carries at leastone axially extending pin 82 which is matable in an arcuate recess 84 inthe bottom wall 86 of the internal carrier 18. When an end wall 88 ofthe recess 84 engages or abuts the pin 82 the carrier 18 will be at itsrotation limit. Rotation of the plate member 26 by the lever member 76will first of all bring the pin 82 into contact with an end wall 88,with continued rotation of the plate member applying a rotative force tothe internal carrier and then to the valve stem and the valve member. 0fcourse, the location of the pin(s) 82 and the recess(es) 84 could bereversed, with the pin(s) depending from the carrier 18 and therecess(es) being in the upper surface of the plate member 26, as in FIG.6B.

Other changes could be effected by a skilled practitioner in the artwithout departing from the essence of the invention. Thus the protectionto be afforded this invention is to be ascertained from the claimsappended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A manual override systemfor a rotary magnetically operated valve assembly having a valve memberrotatably located in a valve body on a rotation axis, a first carriermember connected to said valve member and mounting a peripheral set ofdriven magnets, a barrier member surrounding said carrier member andbeing hermetically sealed to a rotatable lower plate member of saidassembly, a second carrier member surrounding said barrier member andmounting a set of drive magnets for magnetically inducing followingrotary movement in said first carrier member and said valve member inresponse to specific rotary movement of said second carrier member, androtation limit means cooperatively provided on said lower plate memberand said first carrier member, said manual override system comprising: asupport member fixed to said valve body; disengageable means normallyinterconnecting said support member and said lower plate member to holdsaid lower plate member stationary; and lever means engageable with saidlower plate member following disengagement of said disengageable meansfor forcing rotation of said lower plate member and consequent rotationof said valve member through said limit means in the event that saiddrive magnets are unable to effect rotary movement of said drivenmagnets.
 2. The system of claim 1 wherein said first carrier memberincludes a valve stem that interconnects the first carrier member andsaid valve member, said rotation limit means comprising a pin extendingdiametrically beyond said valve stem and at least one cooperating recessin said lower plate member, said recess having end walls against whichsaid pin will abut at the rotation limits of said valve member.
 3. Thesystem of claim 2 wherein said pin extends diametrically at each endthereof beyond said valve stem, there being a recess in said lower platemember for each said end of said pin.
 4. The system of claim 3 whereinsaid disengageable means is a retaining member extendable through andlockable with said support member, said retaining member beingreceivable in a corresponding bore in said lower plate member.
 5. Thesystem of claim 4 wherein said lower plate member includes an annularplate having an annular outer recessed shoulder portion, an annular ringon said shoulder and affixed thereto by a plurality of circumferentiallyspaced bolts, said bore extending radially into said ring, and adepending boss portion bearingly surrounding said valve stem.
 6. Thesystem of claim 5 wherein said lever means comprises an elongated leverarm having an arcuate cutout in one edge thereof matable with saiddepending boss portion, the opposite edge of said lever arm beingengageable with a head of one of said bolts for pushing thereagainst andeffecting rotation of said lower plate member.
 7. The system of claim 1wherein said lower plate member includes a depending boss portion andsaid lever means comprises an elongated lever arm having an arcuatecutout in one edge thereof matable with said depending boss portion, theopposite edge of said lever arm being engageable with abutment meansadjacent the outer periphery of said lower plate member for pushingagainst said abutment means and effecting rotation of said lower platemember.
 8. The system of claim 7 wherein said rotation limit meanscomprises at least one pin extending parallel to said rotation axis fromsaid first carrier member or said lower plate member into acorresponding arcuate recess in said lower plate member or said firstcarrier member, said recess having end walls against which said pin willabut at the rotation limits of said valve member.
 9. The system of claim8 wherein said disengageable means is a pin member extendable throughand lockable with said support member, said pin member being receivablein a corresponding bore in said lower plate member.